Apparatus for drilling well casings



June 12, 1934. c. H.LIEDBECK APPARATUS FOR DRILLING WELL CASINGS Filed Nov. 5, 1951 0 9 6 fi9-a8 3 4. 2 2 1 1.232 5 7 r w 7 7 I? a L Ni u I u m w 7 .8 42 i V 5 z o a .2. 3. w m w M Z a? 3 Patented June '12 1934 I @NITED STATES PATENT OFFlCB Application November 5, 1931, Serial No..573,280 In Germany October 16, 1930 2 Claims.

This invention relates to improvements in apparatus for making a hole through the wall of a casing inserted into a borehole in the ground for oil Well and gas well.

The object of this invention is to provide an improvement in a drilling machine, suspended from the ground level by string or strings of rods or pipes or a combination of both, into a casing inserted into a borehole in the ground for oil well' and gas well and the said drilling machine operated by the said string of rods or pipes or combination of both.

I attain this object by the mechanism illustrated in the accompanying drawing, in which Figs. 1 and 2 are longitudinal sections of one embodiment of such apparatus, all the three embodiments having the same improvement consisting in the springs 3, holding the drilling machine in a rigid position against the walls of the casings they are inserted into, preventing the point of the drill 18 from oscillating about when the point of the drill just commences to make a center, when entering the Wall of the casing, a very important function.

Similar numerals refer to similar -or corresponding parts throughout the several views on the accompanying drawing, in which:

Fig. 1 is a central longitudinal section taken through a preferred embodiment of the invention;

Fig. 2 is a central longitudinal section at righ anglesto Fig. 1; r

Fig. 3 is a central longitudinal section of a modified form of the invention; and

35 Fig. 4 is a central longitudinal section of a further modification.

One embodiment of the apparatus is shown in the sketches Figs. 1 and 2. The apparatus is let down into the borehole in the ground attached onto a single string of rods or pipes, and is operated by the same string of rods or pipes. Onto the threads 1 on the spindle 2 is fastened a pair of preferably light drilling jars,,not shown on this drawing. Above andonto this pair of drilling '45 jars is fastened the string of rods or pipes up to the ground level, and there suspended froman axial ball-bearing in the travelling block in the derrick. v

The apparatus preferably is held in position by the two springs 3, and mostly additionally by a very strong spring attached to the'apparatus and below it by a bolt through the hole 4, thus the apparatus is unable by its own weight to slide down in the casing. The heavy rod above the apparatus, fastened onto it by the pair of Jars,

forces the apparatus down to its position in the borehole, at the same time the string of rods or pipes holds it suspended from the travelling block in the derrick.

When the apparatus has reached its proper level in the casing inserted into the borehole, it is there-rigidly held by the two springs 3 and mostly alsoby the extra strong spring below it, attached to'it by a bolt or pin through the hole 4:. Afterwards the string of rods or pipes, which is attached to the apparatus and is reaching up to the ground level, is elevated about half the stroke of the pair of drilling jars, the apparatus with the relatively weak drill 18 thereby not being afiected by the oscillations of the long string of rods or pipes reaching up to the ground level, therebypreventing the breaking off of the relatively weak drill.

Fig. 1 is a longitudinal section of the apparatus, showing the mechanism inside the shell or body of the apparatus. The body 5 of the apparatus is made in two halves, held together by the threaded coupling 6 and the forkshaped piece 7 with the bolts 8. Fig. 2 is a longitudinal section taken at line B-B.

Having mounted and placed the apparatus at the desired level in the borehole, according to the general considerations herein described, with the string of rods or pipes pulled up about one half the length of the stroke of the pair of drilling rods, the string of rods or pipes at the ground level is caused to revolve. This revolving motion of the string of rods or pipes is transmitted through the heavy rod and pair of jars onto the spindle 2, as the arrow 9 indicates.

The spindle revolves in the body' 5 and is pre-y vented from sliding up and down by the buttress '10. Onto the spindle 2 is fastened a conical gear-. wheel 11, which acts on another conical gearwheel 12, which is fastened onto the axis 13.

Onto this axis 13 are placed the two gearwheels 14 and 15, which grip intotwo other gear-wheels 16 and 17, making a set of differential gears. The aim of this is to have the drill 18 to revolve and gradually to advance as its revolving motion is going on, thus cutting into the wall of the casing the apparatus is inserted into. The feeding out motionof the drill'is caused by the threads 19, in which run the threads on the chuck 20, onto, which chuck the drill is fastened.

A drill 18 of non-circular'cross-section is slidably mounted in the axial bore of the gear-wheel 1'7, but relative rotation of the drill and gearwheel is prevented by a portion of the wall of 4 revolve.

the bore, such asthe tongues 21, which project into longitudinal channels on the drill. The gear-wheel 16 is secured to and preferably integral with the hollow cylinder 22 which carries feed threads 19 that cooperate with the nut 20. Since the gear-wheels I6 and 17 rotate at different angular velocities, the nut 20 and drill 18 will be given a forward feed or a return motion depending upon the directionof rotation of the spindle 2.

That side of the apparatus where the point of the drill 18 comes out of the body, when going to drill, is herecalled the front-side, while the other side just opposite is here called the rearside. The drill 18 will break if it is allowed to oscillate when its point enters the wall of the casing. Two springs 3 are provided to hold the apparatus with the drill 18 inside it, rigidly in the casing, that is to say with the rearside 'of the apparatus pressed against the wall of the easing, either directly or indirectly, preferably through the means of a suitable longitudinal piece of wood, bolted onto the rear-side of the apparatus. When the body of the apparatus is thus held in a fixed position against the wall of the casing it is inserted into, it will prevent oscillation of the point of the drill 18 when it enters the wall of the casing it is going to drill through.

When the drill 18 has done its work and must be drawn back into the body of the apparatus again, the string of rods or pipes at the ground level is caused to revolve reversely, thereby through the spindle 2 and the conical, gearwheels 11 and 12 causing the gear-wheels 14 and 15 to revolve reversely, thereby causing the drill 18 to .return back into the body 5 of the apparatus again.

Fig. 3 is a longitudinal section of another embodiment of an apparatus for the same scope.

Here the apparatus is suspended by a string of pipes 23, which by the conical gear-wheel 24 causes the conical gear-wheel 25 to revolve. Onto this conical gear-wheel 25 is fastened a gearwheel 26, which causes the gear-wheel 27 to revolve. The tongues 21 in this gear-wheel 27 cause the drill 18 to revolve, thus to drill or out.

Inside the string of pipes 23 is lowered down a string of rods or pipes 28, which is to cause the drill to advance out and to return back into the apparatus again, after the hole throughthe wall of the casing has been made. Onto the lower end of 28 is fastened conical gear-wheel 29, which causes another conical gear-wheel 30 to Onto 30 is fastened a gear-wheel 31, which causes another gear-wheel 32 to revolve. Onto 32 is fastened a hollow cylinder 22 with its threads 19. In 19 slide the threads on the chuck piece 33 with its segmental holes 34. Through the segmental holes 34 slide the stands 35 with suitable cross-sections, which stands 35 to revolve. Onto 25 is fastened the gear-wheel 26, which causes the gear-wheel 2'7 to revolve. The tongues 21 in this gear-wheel 27 cause the drill 18 to 'revolve and-drill or cut.

The string of rods or pipes 28 is for the purpose of causing the drill 18 to advance out or to return back into the apparatus again after the hole in the casing is made. Onto the lower end of 28 is fastened a conical gear-wheel 29, which causes another conical gear-wheel 30 to revolve. Onto 30 is fastened a gear-wheel 31, which causes another gear-wheel 32 to revolve. Onto 32 is fastened a hollow cylinder 22 with its threads 19. In 19 slide the threads of the chuck piece 33 with its segmental holes 34. Through 34 slide the segmental shaped stands 35, whichare' fastened to the body 38 of the apparatus.

The gear-wheels can be changed, replaced by proper combination of sprocket wheels with sprocket chains or combination of gear-wheels and sprocket wheels with sprocket chains.

The pair of drilling jars attached to the upper end of the apparatus, can be replaced by a helicoid spring, which takes up the vertical oscillations of the relatively heavy long string of rods or pipes reaching up to the ground level.

The operating of the apparatus may also be caused by a motor placed down in the borehole, but the string of rods or pipes reaching up to the ground level and there revolved is the best.

This invention does not limit itself to the embodiments herein shown, other alternatives are also included.

I claim:

1. In a well casing drilling tool, an elongated body having a lateral opening intermediate the ends thereof, a drill carried by said body, means for rotating said drill and for feeding the same from said opening, spring means carried by said body above and below said opening and in substantial longitudinal alinement therewith, said spring means being adapted to engage the wall of said casing to force said body laterally into frictional engagement therewith in order to prevent movement of the body during the drilling operation.

2. In a well casing drilling tool, a body, a shaft journalled axially in one end of said body and forming suspension means therefor, a spindle mounted within said body at right angles to said shaft and driven thereby, a pair of coaxial interfitting sleeve members journalled in said body, one of said sleeves opening laterally of said body, a drill mounted within said sleeves, said drill having a threaded feeding connection with one of said sleeves and a driving connection with the other, means for driving said sleeves from said spindle at different speeds to simultaneously rotate and feed said drill from said body, spring means mounted adjacent the ends of said body in substantial longitudinal alinement with said laterally opening sleeveend and with each other, said spring means being adapted when said body is lowered into a well casing to force said body into contact with said casing along an area substantially opposite the point at which said drill engages the casing during the drilling operation.

- CARL I-IENRIK LIEDBECK. 

